As the cost of electronic digital storage media has steadily declined, the use of such storage media for storing data, such as directories and the like, has rapidly expanded. Typically such memories include a plurality of data listings, each stored with a corresponding data address. Individual data listings are commonly accessed from the data memory by inputting a complete listing of the pertinent address which is then used to access the data portion of the listing from the data file.
While the address portion of such listings is commonly an arbitrary number designation, used for retrieval purposes only, it has been suggested in the past, as in U.S. Pat. No. 26,919, for example, that a portion of the data may, itself, be used to provide access to the stored data. Such accessing is particularly well adapted, for example, to directory use, such as might be provided by a telephone information bureau. In such cases, the memory stores the name of a telephone owner and the appropriate telephone number, the telephone owner's name being utilized as the access element to search the data file. In such systems, alphabetic characters are input at a keyboard and compared with the telephone owners' names, typically stored alphabetically in the directory listing. When a match occurs, a group of telephone numbers is output to a display panel.
Because these systems do not utilize arbitrary addresses to access the stored data locations, as is common with many computer memories, they simply provide a directory of names and numbers where the directory data itself is searched to select a matching group. Such systems, in the past, have typically required that one entire portion of the stored data element be input at the keyboard for comparison. Thus, in a telephone directory system, the prior art would normally require that the full name of the telephone owner be input to the system for comparison with the name field of the memory to determine whether a match exists.
Even in systems of the prior art which did not require input of the entire name field, prior equipment required that the initial characters input at the keyboard match the initial characters in the stored name field. For example, in the telephone directory embodiment of such devices, it is necessary to input the letters in proper sequence of the telephone owner's last name, followed by his first name, exactly as stored in the telephone directory memory file, in order to determine whether a match exists.
Because of these difficulties associated with the prior art, the use of this type of directory searching system has been limited to uses, such as that described in U.S. Pat. No. 26,919, which provide an output, as to a CRT screen, of plural listings from the directory, from which an operator can select a specific directory listing. Thus, in such prior art systems, as keystroke data is entered, it is compared with file listings and, with sufficient keystroke data, a substantial block of data is output for manual searching.
Such systems, therefore, do not permit a unique selection to be made from the memory, do not permit selection of a unique entry based upon characters which may occur anywhere within the desired listing in the memory, and do not permit the connection of such a system to an automatic telephone dialer, since no unique number is selected.